semper tua
by bravevulnerability
Summary: 'It's been a couple of hours, but his mind is still stuck on the picture of her flirting with Danny Valentine.' An episode insert for 7x22, Dead From New York.


**A/N: Major thanks to the lovely encantadaa for help with the title.**

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A full hour of scrubbing traffic cam footage and they've still come across no sign of the suspect who could have shot Sid, not that he's been paying much attention anyway. Castle rises from his seat in tech room, cracking his spine as he stands, earning the arch of his wife's brow at the sound, but he doesn't answer her amused silence. It's been a couple of hours, but his mind is still stuck on the picture of her flirting with Danny Valentine. The other man's leer as he had raked his eyes over Kate's body from head to toe had had the animalistic urge to _claim_ arising and now thriving in Rick's blood, and while he knows Kate had no real interest in Valentine, he hadn't exactly enjoyed seeing her return the guy's advances.

"Castle?" Kate has the video feed paused, her gaze concerned and resting on him. "You okay?"

"Yeah, fine," he assures her with a halfhearted wave of his hand that fails to convince her in the least.

Kate pushes back from the table, rising to stand beside him and gesturing towards the exit of the small room. "Coffee break?"

He nods, already heading for the door and holding it open for her, but caffeine isn't going to help the pent up irritation bubbling beneath his skin. It's not too late in the evening and the homicide floor is still buzzing with activity, with fellow officers and other open cases, but no one notices when Castle snags her wrist on the way to the break room, draws her down the nearest hallway instead.

"Castle, what are we-"

His fingers tighten around the delicate bone of her wrist and her lips purse, but she doesn't try to tug her hand away, to stop him from dragging her along after him through the blessedly empty hallway, even when he comes to a halt in front of a familiar door at the end of the hall.

Her eyes widen, but he doesn't give her a chance to protest, turning the knob and urging her inside the supply closet before someone can catch sight of them.

"Can't you wait until we get home?" she huffs, shaking her wrist from his fingers and crossing her arms over her chest, but he only locks the door, watches the pools of her eyes darken and her lashes lower to hide the arousal that comes to life whether she wants it to or not. "Obviously, we're getting nowhere with traffic cams so if you're that desperate to-"

He backs her into a shelf of copy paper before she can finish, his knee already sliding between her thighs, his hands already catching her hips to jerk her closer and Kate grips his biceps, arches up on her tiptoes by reflex.

Her eyes flicker up from his mouth, searching his face for a clue to this impromptu meeting in a supply closet they've used a couple of times before, but Castle merely steals his hand beneath her blouse, coasts up the bare skin of her side until his fingers skirt the underwire of her bra. Kate's teeth snag her bottom lip, ribs expanding beneath the heated weight of his palm, suppressing the groan that rises in her throat when his fingers slide beneath the cup of her bra, palming her breast and kneading her nipple with his thumb.

"Oh, I know what this is," she gasps, hooking her ankle at his calf as her head falls back against the shelf. "Jealous, you're jealous-"

His hand squeezes while his lips to descend to the exposed flesh of her neck, sucking on the taut skin beneath her jaw, laving his tongue over the throb of her pulse. She whimpers, one of her hands flying up to tangle in his hair, clutching hard enough to elicit sparks of pain along his scalp, and he bites her for it, sinks his teeth into the tender skin of her throat and relishes in the breathless mewl that claws its way past her lips.

"Not jealous," he growls, nuzzling his way up to her ear, making her jerk with the touch of his tongue to that sensitive spot just behind the soft lobe. "You're already mine."

Her hips thrust against him at that, her pelvis coming into sharp contact with the bulge between them, and he sweeps his hand back down her side, skirts around to the front of her jeans.

"You're being ridiculous," she gets out, craning forward to nip at his chin, her lips spreading into a grin that quickly dissolves when he presses against her once more, grinds his hips into the quivering cradle of hers. "It was just flirting, not-"

"Wasn't the flirting," he mumbles, finally smudging his mouth to hers, capturing her bottom lip and stroking his tongue over the swollen flesh.

He had enjoyed watching her flirt in the past, when he was nothing more than an observer on the outside looking in of her life; he'd thought it was sexy, the way she could have a man wrapped around her finger with a mere flash of her smile or the sultry caress of her gaze. And of course he had witnessed other men flirt with her over the years, he could never exactly blame them, but she was always quick to shut them down for the most part, to remain unattainable. Now, though, she was his and he didn't care if it made him possessive or jealous – Kate Beckett was his wife and he wasn't going to let some washed up TV actor like Valentine charm and lust after her as if the wedding band on her finger meant nothing.

His tongue plunges deep, caressing over hers, and Kate's nails score his shoulder blade while her opposite set of fingers tangle further into his hair, ready to tear the strands from his scalp at this rate.

Her concentration is fading, the haze of lust he knows well clouding her eyes, but she manages to focus long enough to reach down, grab one of the distracted hands toying with the waistline of her jeans. He's already popped open the button of her jeans and she spares a quick glance down to find the zipper, jerking it down and guiding his hand down the flat plain of her abdomen, beneath the line of her underwear.

Castle drops his head to her shoulder as his fingers encounter the heated pool of wetness between her legs, the evidence of how turned on she is dripping onto his digits, scorching against his skin.

"No one else," she croaks, squirming as his fingers begin to move, back and forth through her folds, adding the occasional circle of his thumb to her clit just to witness the uncontrolled ripple of her abdomen against his forearm. "No one else can do this to me."

She moans as two of his fingers slip inside her, the hand still coiled around his wrist clenching hard.

"Do what to you?" he demands, gruff in her ear, and her eyes slit open, the coals of her pupils simmering with gold around the edges as she stares at him, holding to his gaze even as his fingers work her slowly, in and out, massaging her walls, driving her insane in the best way he knows how. "What do I do to you that no one else can?"

"You already know," she grits out, releasing his arm to unbuckle his belt, shoving at his jeans with trembling hands, dragging his boxers down his thighs. Castle allows her to push him back, relishing in her whine at the loss of contact when his hand slips from her panties, gives her room to kick out of her boot and helps her extract one long leg from the confines of her jeans, her underwear.

His damp fingers clutch at her thigh, hefting the limb up to hook at his waist with practiced ease, but her attention is on the hand currently curling around his pulsing length, on the lurch of his hips into the coil of her palm. He grits his teeth as she guides him forward, his cock already straining to meet her, but he's never prepared for the way she teases the tip of him through the heat of her folds, draws a moan from his throat that syncs with the matching sound of hers. But he's done with foreplay, done waiting, and squeezes the back of her knee in warning right before he pushes inside her.

Kate's arm slide beneath his dress shirt, the heat of her palms branding as they splay at the naked skin of his back, gliding up to coil up and around his shoulders. He knots his free hand in her hair, devastating the perfectly straightened strands in his fist and using his grip to angle her mouth, to deepen the kiss he lays there.

"Say it," he mutters around the clash of their mouths, slamming his hips into hers, setting a brutal rhythm that she arches and surges into, taking just as much as she gives.

"Fuck, Rick," she pants as she nips and suckles at his upper lip, claws at his skin with her nails, hard enough to send fissures of pain spiraling with the pleasure in his bloodstream. Her eyes fight to flutter open, lashes flickering, twining with his, and for a second, he's distracted by how beautiful she is pinned to a shelf of office supplies with her gaze fierce and needful on his while her hips dance to the punishing pace of their lower bodies.

But he can still see Danny Valentine looking at her like a starved vulture ready to eat her alive.

"Tell me what only I can do to you, Kate," he growls, lifting his hand from her knee to snake between them, palming her breast through the thin material of her button up, catching the keen that climbs her throat with his teeth. "Tell me-"

"This," she chokes out, so close, her entire body already threatening to seize, to be swept away with the orgasm building within them both. "Make me - like this," she adds, breathless and clinging to him, crushing him against her until he can practically feel the crash of her heart against the cage of her ribs. "Only you can make me like this, only you, just you-"

The words shove him over the edge along with the twist of her hips, drag him under the white-hot wave of arousal that sends black spots dancing through his vision, and he barely has the energy to cover her mouth, swallow her sob of release.

Castle staggers, gasping harsh through the final tremors of her body against his, and holds her up as their heartbeats start to slow and their breathing begins to settle, buries his face in her hair when she nuzzles her cheek to the wrinkled fabric of his collar.

"Convinced now?" she hums into the hollow of his throat, pressing her lips there and dipping her tongue to the spot to evoke the shudder she knows will ripple down his spine.

He sweeps his hand downwards to graze beneath the hem of her disheveled blouse, fingers brushing at the swell of her ass and earning a lazy nip of her teeth to his clavicle. "Thoroughly."

"Good, because I'm ready to go home," she murmurs, easing the leg draped at his thigh down until her toes dip back into the pool of denim and black cotton at their feet.

"What about the traffic cam footage?" Castle asks, holding her steady as he steps back, smearing one last kiss to her lips when she grunts at the loss of him.

"As I was saying earlier, I don't think we're going to find anything. I'd rather just wait to hear from Ryan and Esposito, see if they find anything in the alley," she explains, sliding her jeans back up the length of her legs while he does the same, fumbling with his belt buckle while Kate attempts to readjust her shirt and the ruined mess of her hair.

She swats at his hand when he tries to smooth down the tousled strands, plucks a hairband from her wrist and ties it into a quick bun at her nape instead. Castle's the one to check if the coast is clear, finding the hallway empty and slipping out of the closet, heading straight for the tech room while Kate starts for her desk. She retrieves her jacket and her messenger bag as he powers off the computers, flips the light switch and meets her in front of the elevator.

Her face is neutral as they step inside the lift, a blank slate not a single person in the precinct could decipher, but once the doors push closed, Kate's arm loops through his and a mischievous smirk spreads across her lips.

"What?" he chuckles, nudging her with his elbow, but she shakes her head, lifts a hand to sweep back a stray lock of hair that becomes twined around her fingers, twirling the strand even as they doors slide open into the lobby.

"You just make the supply closet pretty appealing," she admits, strolling with him out into the chilly night air, failing to hide the upturned corners of her mouth as they continue down the sidewalk towards her parked car a few feet away.

"Really? Because I think I got a stapler to the knee at one point," he muses, grinning at the roll of her eyes.

"Your own fault," Kate returns, retrieving her keys from her back pocket and unlocking the Charger. "So intent on being a possessive bully."

Castle gapes at her, but her lips are still curled, her eyes dancing with leftover arousal and gentle amusement, so he steps into her just as he had in the supply closet only minutes earlier, backs her up against the driver's side of the car.

"No one gets to touch you but me."

Her eyes flash with heat and approval, secret delight in her gaze as it flicks down to his mouth, alights a fresh wave of need in his groin.

"He never would have had a chance, Castle," she murmurs, husks, drifting forward to take from his mouth for just a moment. "Not his to touch."

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 _semper tua - always yours_


End file.
